Sector-shaped section of continuous casting machine for heavy reduction of solidified terminal of continuously cast slab and heavy reduction method thereof

ABSTRACT

The present invention provides a sector-shaped section of a continuous casting machine for heavy reduction of a solidified terminal of a continuously cast slab and a heavy reduction method. The sector-shaped section of a continuous casting machine comprises an upper frame, a lower frame, an upper driving roller, a lower driving roller, a left driven roller set, a right driven roller set, a screw-down gear and clamping cylinders which are positioned on the sector-shaped section; the clamping cylinders are used for clamping the upper frame and the lower frame and keeping the upper frame and the lower frame at a set interval; the upper driving roller is connected with the screw-down gear; the upper driving roller is connected to the upper frame through a bearing base; the lower driving roller is connected to the lower frame through a bearing base; the left driven roller set and the right driven roller set, are respectively positioned on two sides of the driving rollers; the left driven roller set is used for clamping the cast slab before reduction; the right driven roller set is used for clamping the cast slab after reduction; and the diameter ratio of the driving rollers to the driven rollers is 1.1:1-2:1. The deformation permeability of the present invention is increased, equivalent to the deformation of one rolling pass of a two-roller mill with a relatively large roller diameter, which facilitates improvement on the looseness and segregation of the center area of the continuously cast slab.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/CN2014/087369 with a filing date of Sep. 25, 2014, designatingthe United States, now pending, and further claims priority to ChinesePatent Application No. 201410325414.1 with a filing date of Jul. 9,2014. The content of the aforementioned applications, including anyintervening amendments thereto, are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to the technical field of slab casting, inparticular to a sector-shaped section of a continuous casting machinefor heavy reduction of a solidified terminal of a continuously cast slaband a heavy reduction method thereof.

BACKGROUND OF THE PRESENT INVENTION

The technology for heavy reduction of the solidified terminal of thecontinuously cast slabs refers to a process of arranging screw-downrollers at a solidified terminal of a continuously cast slab on acontinuous casting line, applying heavy-reduction deformation (5-20 mmto the cast slab when the solid phase rate of the center of the castslab exceeds 80%, and then performing normal rolling production. Thetechnology can obviously improve the center quality (improvemacro-structure, shrink holes, looseness, segregation, etc.) of thecontinuously cast slabs, and can produce quality extra-thick productswith a thickness of over 100 mm at a relatively low compression ratio(1.5-2.5).

When heavy reduction is applied to the solidified terminal of thecontinuously cast slab, if the sector-shaped section of a castingmachine adopts overall heavy reduction, the contact area obviouslyincreases while 5-7 pairs of casting rollers of the sector-shapedsection contact the slab at the same time, followed by the obviousincrease in the load, so the strength and rigidity of the sector-shapedsection must be greatly enhanced to resist the large load on and largeelastic deformation of the sector-shaped section and the segmentedroller (or casting roller). The segmented roller is comprised of a rollcollar, a core shaft and a middle support bearing base, which greatlyincreases the dimension and weight of the sector-shaped section, thuscausing a series of new problems to the lifting, assembling andmaintenance of the sector-shaped section. Besides, the heavy reductionis carried out near the solidified terminal of the continuously castslab, and the deformation (strain) generated when the multiple pairs ofroller of the heavy reduction sector-shaped, section performsmall-deformation reduction is of poor permeability, and the straintransmitted to the center area of the continuously casting slab issmall, which cannot better help improve the looseness and segregationdefects of the center area.

Therefore, when the soft reduction system of the existing continuouscasting machine is employed to perform heavy reduction on the solidifiedterminal of the sector-shaped section of the continuous casting machine,problems including seriously insufficient strength and rigidity of thesector-shaped section and driving rollers of the continuous castingmachine, insufficient bearing capability of the clamping cylinders,difficulties in implementation of the heavy reduction on the solidifiedterminal, and the trend of cracking in the middle of the cast slabappear.

SUMMARY OF PRESENT INVENTION

The technical problem to be solved by the present invention is toprovide a continuous casting machine for heavy reduction of a solidifiedterminal of a continuously cast slab and a heavy reduction methodthereof, to overcome defects in the prior art including seriouslyinsufficient strength and rigidity of the sector-shaped section anddriving rollers of the continuous casting machine, insufficient bearingcapability of the clamping cylinders, difficulties in implementation ofthe heavy reduction on the solidified terminal and trend of cracking inthe middle of the cast slab when the sector-shaped section of theexisting continuous casting machine is employed to perform heavyreduction on the solidified terminal.

To solve the above technical problems, an embodiment of the presentinvention provides a sector-shaped section of a continuous castingmachine for heavy reduction of a solidified terminal of a continuouslycast slab, comprising an upper frame, a lower frame, an upper drivingroller, a lower driving roller, a left driven roller set, a right drivenroller set, a screw-down gear and clamping cylinders which arepositioned on the sector-shaped section of the continuous castingmachine. The clamping cylinders are used for clamping the upper frameand the lower frame and keeping the upper frame and the lower frame at aset interval. The upper driving roller is connected with the screw-downgear. The upper driving roller is connected to the upper frame throughan upper bearing base. The lower driving roller is connected to thelower frame through a lower bearing base. The left driven roller set andthe right driven roller set are respectively positioned on two sides ofthe driving rollers. The left driven roller set is used for clamping thecast slab before reduction. The right driven roller set is used forclamping the cast slab after reduction. The diameter ratio of thedriving rollers to the driven rollers is 1.1:1-2:1.

According to the present invention, the opening degrees of the rightdriven roller set and the driving rollers are identical with thethickness of the cast slab after reduction.

According to the present invention, the opening degree of the leftdriven roller set is identical with the thickness of the cast slabbefore reduction.

According to the present invention, the driving rollers are integratedand manufactured through an integral forming process.

To solve the above technical problems, the present invention alsoprovides a method for heavy reduction of a solidified terminal of acontinuously cast slab, characterized by comprising the following steps:

(1) applying a certain pressure to the upper frame via the clampingcylinders such that the opening degree of the left driven roller set isidentical with the thickness of the cast slab before reduction, andclamping the cast slab before reduction via the clamping cylinders;

(2) setting the rolling reduction to 5-20 mm, operating the screw-downgear to drive the driving rollers to apply heavy reduction onto the castslab and to deform the cast slab;

(3) adjusting the right driven roller set such that the opening degreethereof equals the interval between the upper and lower driving rollers,and clamping the cast slab after reduction by the right driven rollerset.

In the above solution, the present invention adopts large-diameterintegrated driving rollers, the upper frame and the lower frame whichhave high strength and high rigidity, and clamping cylinders with highbearing capabilities; during implementation of the heavy reduction, thetotal deformation is the deformation generated when the large-diameterdriving rollers perform heavy reduction on the continuously cast slab,not the total deformation usually generated when the heavy reduction isgradually completed by 5-7 pairs of casting rollers of the sector-shapedsection one by one.

The technical solution of the present invention has the followingbeneficial effects:

1. The contact area is reduced during the plastic deformation, and onlythe large-diameter integrated driving rollers screw down, so the totaldeformation force is obviously reduced.

2. The clamping force added via the clamping cylinders of thesector-shaped section is correspondingly reduced; meanwhile, structuralmaterials and weight added to maintain the strength and the rigidity inthe process of implementing the heavy reduction by the upper and lowersector-shaped sections are also reduced.

3. The deformation permeability is increased, equivalent to thedeformation of one rolling pass of a two-roller mill with a relativelylarge roller diameter, which facilitates improvement on the loosenessand segregation of the center area of the continuously cast slab.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a sector-shaped section of a continuouscasting machine for heavy reduction of a solidified terminal of acontinuously cast slab of an embodiment of the present invention;

FIG. 2 is a lateral view of a sector-shaped section of a continuouscasting machine for heavy reduction of a solidified terminal of acontinuously cast slab of an embodiment of the present invention; and

FIG. 3 is a schematic diagram of a heavy reduction method for asector-shaped section of a continuous casting machine for heavyreduction of a solidified terminal of a continuously cast slab of anembodiment of the present invention.

DESCRIPTION OF THE MAIN COMPONENTS

1 Screw-down gear: 2; Upper frame; 3: Upper driving roller; 4: Upperbearing base; 5: Lower driving roller; 6: Lower bearing base; 7: Lowerframe; 8: Left driven roller set; 9: Right driven roller set; 10:Clamping cylinder; 11: Transmission device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In order to clarify the technical problems to be solved, the technicalsolution and the advantage of the present invention, the presentinvention is described in detail below in conjunction with the attacheddrawings and specific embodiments.

The present invention provides a sector-shaped section of a continuouscasting machine for heavy reduction of a solidified terminal of acontinuously cast slab and a heavy reduction method thereof to solveproblems in the prior art including seriously insufficient strength andrigidity of the sector-shaped section and driving rollers of thecontinuous casting machine, insufficient bearing capability of theclamping cylinders, difficulties in implementation of the heavyreduction on the solidified terminal, the trend of cracking in themiddle of the cast slab when the soft reduction system of the existingcontinuous casting machine is employed to perform heavy reduction on thesolidified terminal of the sector-shaped section.

As shown in FIG. 1 and FIG. 2, an embodiment of the present inventionprovides a sector-shaped section of a continuous casting machine forheavy reduction of a solidified terminal of a contnuously cast slab,including an upper frame 2, a lower frame 7, an upper driving roller 3,a lower driving roller 6, a left driven roller set, 8, a right drivenroller set 9, a screw-down gear 1 and clamping cylinders 10 which arepositioned on the sector-shaped section of the continuous castingmachine. The clamping cylinders 10 are used for clamping the upper frame2 and the lower frame 7 and keeping the upper frame 2 and the lowerframe 7 at a set interval. The driving rollers and the driven rollersare driven to rotate by a transmission device 11, thus driving the castslab to move forward. The upper driving roller 3 is connected with thescrew-down gear 1. The upper driving roller 3 is connected to the upperframe 2 through an upper bearing base 4. The lower driving roller 5 isconnected to the lower frame 7 through a lower bearing base 6. The leftdriven roller set 8 and the right driven roller set 9 are respectivelypositioned on two sides of the driving rollers. The left driven rollerset 8 is used for clamping the cast slab before reduction. The rightdriven roller set 9 is used for clamping the cast slab after reduction.The diameter ratio of the driving rollers to the driven rollers is1.1:1-2:1.

The opening degrees of the right driven roller set 9 and the drivingrollers are identical with the thickness of the cast slab afterreduction. The opening degree of the left driven roller set 8 isidentical with the thickness of the cast slab before reduction. Thedriving rollers are integrated and manufactured through an integralforming process.

As shown in FIG. 3, the present invention also provides a method forheavy reduction of a solidified terminal of a continuously cast slab,including the following steps:

(1) applying a certain pressure to the upper frame 2 via the clampingcylinders such that the opening degree of the left driven roller set 8is identical with the thickness of the cast slab before reduction, andclamping the cast slab before reduction via the clamping cylinders;

(2) setting the rolling reduction to 5-20 mm, operating the screw-downgear 1 to drive the driving rollers to apply heavy reduction onto thecast slab and to deform the cast slab;

(3) adjusting the right driven roller set 9 such that the opening degreethereof equals the interval between the upper and lower driving rollers,and clamping the cast slab after reduction by the right driven rollerset. In this way, the reduction and deformation are only carried out bythe large-diameter integrated driving roller 3, while the right drivenrollers 9 on the exit side do not screw down and implement deformation.Such reduction mode is similar to the rolling deformation of the castslab carried out by the two-roller mill.

The driving rollers of the present invention are large-diameterintegrated driving rollers (namely, not segmented rollers assembled byroll collars, core shafts and middle support bearing bases). Meanwhile,considering the increase in loads when the heavy reduction isimplemented, the strength and rigidity of the upper frame 2 and thelower frame 7 of the sector-shaped section are enhanced (by 2-5 times),and the bearing capabilities of the four clamping cylinders 10 arecorrespondingly enhanced (by 2-5 times).

In the above solution, the present invention adopts large-diameterintegrated driving rollers, the upper frame and the lower frame whichhave high strength and high rigidity, and clamping cylinders with highbearing capabilities; during implementation of the heavy reduction, thetotal deformation is the deformation generated when the large-diameterdriving rollers perform heavy reduction on the continuously cast slab,not the total deformation usually generated when the heavy reduction isgradually completed by 5-7 pairs of casting rollers of the sector-shapedsection one by one.

The technical solution of the present invention has the followingbeneficial effects:

1. The contact area is reduced during the plastic deformation, and onlythe large-diameter integrated driving rollers screw down, so the totaldeformation force is obviously reduced.

2. The clamping force added via the clamping cylinders of thesector-shaped section is correspondingly reduced; meanwhile, structuralmaterials and weight added to maintain the strength and the rigidity inthe process of implementing the heavy reduction by the upper and lowersector-shaped sections are also reduced.

3. The deformation permeability is increased, equivalent to thedeformation of one rolling pass of a two-roller mill with a relativelylarge roller diameter, which facilitates improvement on the loosenessand segregation of the center area of the continuously cast slab.

The above embodiments are just preferable embodiments of the presentinvention. It should be noted that, for those ordinarily skilled in theart, various improvements and changes can be made on the basis of theprinciple of the present invention. The improvements and changes shallalso fall within the protective scope of the present invention.

We claim:
 1. A sector-shaped section of a continuous casting machine forheavy reduction of a solidified terminal of a continuously cast slab,comprising an upper frame, a lower frame, an upper driving roller, alower driving roller, a left driven roller set, a right driven rollerset, a screw-down gear and clamping cylinders which are positioned onthe sector-shaped section of the continuous casting machine,characterized in that the clamping cylinders are used for clamping theupper frame and the lower frame and keeping the upper frame and thelower frame at a set interval; the upper driving roller is connectedwith the screw-down gear; the upper driving roller is connected to theupper frame through an upper bearing base; the lower driving roller isconnected to the lower frame through a lower bearing base; the leftdriven roller set and the right driven roller set are respectivelypositioned on two sides of the driving rollers; the left driven rollerset is used for clamping the cast slab before reduction; the rightdriven roller set is used for clamping the cast slab after reduction;and the diameter ratio of the driving rollers to the driven rollers is1.1:1-2:1.
 2. The sector-shaped section of a continuous casting machinefor heavy reduction of a solidified terminal of a continuously cast slabaccording to claim 1, wherein the opening degrees of the right drivenroller set and the driving rollers are identical with the thickness ofthe cast slab after reduction.
 3. The sector-shaped section of acontinuous casting machine for heavy reduction of a solidified terminalof a continuously cast slab according to claim 2, wherein the openingdegree of the left driven roller set is identical with the thickness ofthe cast slab before reduction.
 4. The sector-shaped section of acontinuous casting machine for heavy reduction of a solidified terminalof a continuously cast slab according to claim 3, wherein the drivingrollers are integrated and manufactured through an integral formingprocess.
 5. A method for heavy reduction of a solidified terminal of acontinuously cast slab, characterized by comprising the following steps:(1) applying a certain pressure to the upper frame via the clampingcylinders such that the opening degree of the left driven roller set isidentical with the thickness of the cast slab before reduction, andclamping the cast slab before reduction via the clamping cylinders; (2)setting the rolling reduction to 5-20 mm, operating the screw-down gearto drive the driving rollers to apply heavy reduction onto the cast slaband to deform the cast slab; (3) adjusting the right driven roller setsuch that the opening degree thereof equals the interval between theupper and lower driving rollers, and clamping the cast slab afterreduction by the right driven roller set.